With spinal stenosis, the spinal canal narrows and pinches the spinal cord and nerves, causing pain in the back and legs. Typically, with age, a person's ligaments may thicken, intervertebral discs may deteriorate and facet joints may break down-all contributing to the condition of the spine characterized by a narrowing of the spinal canal. Injury, heredity, arthritis, changes in blood flow and other causes may also contribute to spinal stenosis.
Doctors have been at the forefront with various treatments of the spine including medications, surgical techniques and implantable devices that alleviate and substantially reduce debilitating pain associated with the back. In one surgical technique, a spacer is implanted between adjacent spinous processes of a patient's spine. The implanted spacer opens the foramen and spinal canal, maintains the desired distance between vertebral body segments, and as a result, avoids impingement of nerves and relieves pain. For suitable candidates, an implantable interspinous spacer may provide significant benefits in terms of pain relief. However, there is a need for an implantable interspinous spacer for patients with adjacent spinous processes that are not aligned such as in patients suffering with scoliosis. Scoliosis is the lateral or sideways curvature caused by congenital, neuromuscular, idiopathic, syndromic or postural conditions. An example of a scoliotic spine is shown in FIG. 12.
Any surgery is an ordeal. However, the type of device and how it is implanted has an impact. For example, one consideration when performing surgery to implant an interspinous spacer is the size of the incision that is required to allow introduction of the device. Small incisions and minimally invasive techniques are quick and generally preferred as they affect less tissue and result in speedier recovery times. As such, there is a need for interspinous spacers that work well with surgical techniques that are minimally invasive for a patient with misaligned spinous processes such as patients with scoliosis. The present invention sets forth such a spacer.